Warbling Vireo (Vireo gilvus) - HBW 15, p. 429

Taxonomy:Muscicapa gilva Vieillot, 1808, New York State, USA. Sometimes placed in a separate genus, Melodivireo. May form a superspecies with V. leucophrys, and often considered conspecific, but the two differ in plumage and some vocalizations. Nominate race has been treated as representing a single monotypic species, the other four races together forming a separate species, on basis of an alleged degree of reproductive isolation of the two taxa in overlap zone in S Canada (Alberta); further study required. Proposed race leucopolius, described from W USA (Warner Mts, in SE Oregon), considered synonymous with swainsoni; pet.. View all taxonomy...

Taxonomy: Muscicapa gilva Vieillot, 1808, New York State, USA. Sometimes placed in a separate genus, Melodivireo. May form a superspecies with V. leucophrys, and often considered conspecific, but the two differ in plumage and some vocalizations. Nominate race has been treated as representing a single monotypic species, the other four races together forming a separate species, on basis of an alleged degree of reproductive isolation of the two taxa in overlap zone in S Canada (Alberta); further study required. Proposed race leucopolius, described from W USA (Warner Mts, in SE Oregon), considered synonymous with swainsoni; petrorus (from Wyoming, in USA) and connectens (from Chilpancingo, in Guerrero, in SW Mexico) both subsumed in brewsteri. Five subspecies recognized.